Field of the Invention
One embodiment of the present invention relates to an audio output device. Another embodiment of the present invention relates to headphones and a headphone system.
Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input/output device (e.g., a touch panel), a method for driving any of them, and a method for manufacturing any of them.
Description of the Related Art
Portable information terminals including cellular phones and portable music players have been spread, and it becomes possible to listen audio contents, e.g., music and a language course, in various locations by carrying them. For example, it is possible to enjoy listening to audio contents by using headphones in travel by train or in sports such as running.
The functions of headphones are being increased and varied. Specifically, improvement in sound quality, reduction in weight, and reduction in noise from the outside are achieved in headphones, and wireless headphones and the like are developed.
For example, Patent Document 1 discloses headphones which are highly convenient when the user wearing the headphones has a conversation.